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7903A – AVR – 2006/02

AVR’s Power-on Reset (POR) triggers at ~1.0V. If a power supply voltage drop should

occur while in sleep mode with the BOD disabled, the SRAM and register contents will be

valid until a POR occurs. A POR will enable the BOD again and set the POR flag to be

read by the application firmware.

The BOD disable feature completely eliminates any power consumption penalty for the

BOD during sleep mode and the MCU has full protection in active mode.

Ultra Low Power 32 kHz Crystal Oscillator

Since the time spent in active mode can be insignificant compared to the time spent in

Power Save mode, Power Save mode is often the most important power consumption

characteristic of a microcontroller. The latest 32 kHz crystal oscillator design utilized in the

AVR MCUs reduces the current consumption in Power Save mode to a level comparable

to Power Down mode.

Competing microcontrollers offer Power Save current consumption as low as 700 nA,

including the oscillator and BOD. With a supply voltage of 1.8 volts, the AVR picoPower

technology achieves the industry’s lowest Power Save current consumption of 650 nA with

the 32 kHz oscillator running and a sleeping BOD.